This study will be used to validate dynamic PET imaging of 18FDG uptake in muscle for measurement of glucose transport & phosphorylation. Once the technique is validated it will be used to assess glucose transport in the insulin resistance associated with NIDDM & obesity. Results from the PET studies will be related to immunohistochemical studies in which Glut 4 is labeled & identified by quantitative confocal laser microscopy imaging of vastus laterialis muscle obtained by percutaneous biopsy.